Neuro 10.3 Strokes Flashcards
What is the definition of a stroke?
The damaging or killing of brain cells starved of oxygen as a result of the blood supply to that part of the brain being cut off
What is a TIA?
A stroke that recovers within 24 hours from the onset of symptoms
Name possible locations for origins of clots
- carotid arteries
- vertebral/basilar arteries
- heart: valvular disease/AF
- the aorta
What is encompassed by the anterior circulation and posterior circulation?
- Fed by internal carotid
- Encompasses the ACA and MCA
- Fed from vertebral arteries
- Encompasses: PCA, cerebellar arteries, arteries supplying the brainstem
In anterior circulation:
- What artery has been affected?
- What area of brain does it supply?
- What does this part of brain do?
- Anterior cerebral artery
- supplies: medial aspects of frontal and parietal lobe and anterior part of corpus callosum
- supplies motor and sensory function to lower limb and genitals
How will a patient present in anterior cerebral artery stroke?
- Motor loss: contralateral, lower limb affected more than upper limb, initially get flaccid paralysis followed later by spasticity (UMN signs)
- Sensory loss: contralateral, loss of all sensory modalities in the lower limb (spinothalamic and dorsal column affected equally)
What are two important areas to know about when talking about Ant cerebral artery strokes?
- Paracentral lobules: area of medial cortex that controls voluntary portion of mircturition, damage leads to loss of voluntary control
- Corpus callosum: damage to ACA can lead to split brain syndrome/alien hand syndrome
Middle cerebral artery strokes
-what area does the brain supply?
- Superior temporal lobe, lateral aspects of frontal and parietal lobe
- basal ganglia, internal capsule, macular cortex
Middle cerebral artery strokes
- what does this part of the brain do?
- what occurs in main trunk occlusions?
- MCA supplies all of the homonculus not supplied by ACA (not legs or genitals)
- MTOs cause considerable cerebral oedema - may lead to coma/death
Middle cerebral artery strokes
-How will the patient present?
- Motor loss: contralateral, upper limb and face affected more than lower limb. Initially get flaccid paralysis followed later by spasticity (UMN signs)
- Sensory loss: contralateral, loss of all sensory modalities in the upper limb and face.
Middle cerebral artery strokes
-Why is the location of occlusion important?
- Proximal occlusion: will affected lateral motor cortex and internal capsule (carries descending motor fibres from the enterito of the motor cortex), t/f face, arm and leg may be affected (lenticulostriate arteries are affected)
- More distal occlusion (after lenticulostriate arteries): spares the internal capsule but still damages the lateral motor cortex t/f only arm and face are affected
Middle cerebral artery strokes
-What are the visual effects?
- Proximal occlusion of MCA: contralateral homonymous hemianopia (temporal and parietal radiations are lost)
- Distal occlusion of MCA: contralateral homonymous superior or inferior quadrantonopia (very rare)
Middle cerebral artery strokes
-how is speech affected?
- Speech centres normally reside in LHS of brain, but symptoms depend on which branch of MCA is affected and which is the dominant hemisphere
- If dominant hemisphere is affected
- Proximal occlusion: global aphasia caused by main trunk occlusion
- Distal occlusion: Brocca’s (expressive) alphasia (leads to motor loss) and/or Wernicke’s (receptor) aphasia (pt speaks rubbish)
Middle cerebral artery strokes
-Speech: what happens if the non-dominant (right is most likely) side is affected?
- Get hemispatial neglect
- tacticle extinction: touch both sides together - get extinction of LHS stimulus
- visual extinction
- Anosognosia
- *Are without Disease knowledge and deny they have any form of disability
Posterior cerebral artery
-What area of the brain does it supply?
-inferior temporal lobe and occipital lobe
